Mercurial > hg
view mercurial/pathutil.py @ 37443:65250a66b55c
revlog: move censor logic into main revlog class
Previously, the revlog class implemented dummy methods for
various censor-related functionality. Revision censoring was
(and will continue to be) only possible on filelog instances.
So filelog implemented these methods to perform something
reasonable.
A problem with implementing censoring on filelog is that
it assumes filelog is a revlog. Upcoming work to formalize
the filelog interface will make this not true.
Furthermore, the censoring logic is security-sensitive. I
think action-at-a-distance with custom implementation of core
revlog APIs in derived classes is a bit dangerous. I think at
a minimum the censor logic should live in revlog.py.
I was tempted to created a "censored revlog" class that
basically pulled these methods out of filelog. But, I wasn't
a huge fan of overriding core methods in child classes. A
reason to do that would be performance. However, the censoring
code only comes into play when:
* hash verification fails
* delta generation
* applying deltas from changegroups
The new code is conditional on an instance attribute. So the
overhead for running the censored code when the revlog isn't
censorable is an attribute lookup. All of these operations are
at least a magnitude slower than a Python attribute lookup. So
there shouldn't be a performance concern.
Differential Revision: https://phab.mercurial-scm.org/D3151
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 05 Apr 2018 16:31:45 -0700 |
parents | d3b893ec5f08 |
children | 21be76e07148 |
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from __future__ import absolute_import import errno import os import posixpath import stat from .i18n import _ from . import ( encoding, error, pycompat, util, ) def _lowerclean(s): return encoding.hfsignoreclean(s.lower()) class pathauditor(object): '''ensure that a filesystem path contains no banned components. the following properties of a path are checked: - ends with a directory separator - under top-level .hg - starts at the root of a windows drive - contains ".." More check are also done about the file system states: - traverses a symlink (e.g. a/symlink_here/b) - inside a nested repository (a callback can be used to approve some nested repositories, e.g., subrepositories) The file system checks are only done when 'realfs' is set to True (the default). They should be disable then we are auditing path for operation on stored history. If 'cached' is set to True, audited paths and sub-directories are cached. Be careful to not keep the cache of unmanaged directories for long because audited paths may be replaced with symlinks. ''' def __init__(self, root, callback=None, realfs=True, cached=False): self.audited = set() self.auditeddir = set() self.root = root self._realfs = realfs self._cached = cached self.callback = callback if os.path.lexists(root) and not util.fscasesensitive(root): self.normcase = util.normcase else: self.normcase = lambda x: x def __call__(self, path, mode=None): '''Check the relative path. path may contain a pattern (e.g. foodir/**.txt)''' path = util.localpath(path) normpath = self.normcase(path) if normpath in self.audited: return # AIX ignores "/" at end of path, others raise EISDIR. if util.endswithsep(path): raise error.Abort(_("path ends in directory separator: %s") % path) parts = util.splitpath(path) if (os.path.splitdrive(path)[0] or _lowerclean(parts[0]) in ('.hg', '.hg.', '') or pycompat.ospardir in parts): raise error.Abort(_("path contains illegal component: %s") % path) # Windows shortname aliases for p in parts: if "~" in p: first, last = p.split("~", 1) if last.isdigit() and first.upper() in ["HG", "HG8B6C"]: raise error.Abort(_("path contains illegal component: %s") % path) if '.hg' in _lowerclean(path): lparts = [_lowerclean(p.lower()) for p in parts] for p in '.hg', '.hg.': if p in lparts[1:]: pos = lparts.index(p) base = os.path.join(*parts[:pos]) raise error.Abort(_("path '%s' is inside nested repo %r") % (path, pycompat.bytestr(base))) normparts = util.splitpath(normpath) assert len(parts) == len(normparts) parts.pop() normparts.pop() prefixes = [] # It's important that we check the path parts starting from the root. # This means we won't accidentally traverse a symlink into some other # filesystem (which is potentially expensive to access). for i in range(len(parts)): prefix = pycompat.ossep.join(parts[:i + 1]) normprefix = pycompat.ossep.join(normparts[:i + 1]) if normprefix in self.auditeddir: continue if self._realfs: self._checkfs(prefix, path) prefixes.append(normprefix) if self._cached: self.audited.add(normpath) # only add prefixes to the cache after checking everything: we don't # want to add "foo/bar/baz" before checking if there's a "foo/.hg" self.auditeddir.update(prefixes) def _checkfs(self, prefix, path): """raise exception if a file system backed check fails""" curpath = os.path.join(self.root, prefix) try: st = os.lstat(curpath) except OSError as err: # EINVAL can be raised as invalid path syntax under win32. # They must be ignored for patterns can be checked too. if err.errno not in (errno.ENOENT, errno.ENOTDIR, errno.EINVAL): raise else: if stat.S_ISLNK(st.st_mode): msg = (_('path %r traverses symbolic link %r') % (pycompat.bytestr(path), pycompat.bytestr(prefix))) raise error.Abort(msg) elif (stat.S_ISDIR(st.st_mode) and os.path.isdir(os.path.join(curpath, '.hg'))): if not self.callback or not self.callback(curpath): msg = _("path '%s' is inside nested repo %r") raise error.Abort(msg % (path, pycompat.bytestr(prefix))) def check(self, path): try: self(path) return True except (OSError, error.Abort): return False def canonpath(root, cwd, myname, auditor=None): '''return the canonical path of myname, given cwd and root >>> def check(root, cwd, myname): ... a = pathauditor(root, realfs=False) ... try: ... return canonpath(root, cwd, myname, a) ... except error.Abort: ... return 'aborted' >>> def unixonly(root, cwd, myname, expected='aborted'): ... if pycompat.iswindows: ... return expected ... return check(root, cwd, myname) >>> def winonly(root, cwd, myname, expected='aborted'): ... if not pycompat.iswindows: ... return expected ... return check(root, cwd, myname) >>> winonly(b'd:\\\\repo', b'c:\\\\dir', b'filename') 'aborted' >>> winonly(b'c:\\\\repo', b'c:\\\\dir', b'filename') 'aborted' >>> winonly(b'c:\\\\repo', b'c:\\\\', b'filename') 'aborted' >>> winonly(b'c:\\\\repo', b'c:\\\\', b'repo\\\\filename', ... b'filename') 'filename' >>> winonly(b'c:\\\\repo', b'c:\\\\repo', b'filename', b'filename') 'filename' >>> winonly(b'c:\\\\repo', b'c:\\\\repo\\\\subdir', b'filename', ... b'subdir/filename') 'subdir/filename' >>> unixonly(b'/repo', b'/dir', b'filename') 'aborted' >>> unixonly(b'/repo', b'/', b'filename') 'aborted' >>> unixonly(b'/repo', b'/', b'repo/filename', b'filename') 'filename' >>> unixonly(b'/repo', b'/repo', b'filename', b'filename') 'filename' >>> unixonly(b'/repo', b'/repo/subdir', b'filename', b'subdir/filename') 'subdir/filename' ''' if util.endswithsep(root): rootsep = root else: rootsep = root + pycompat.ossep name = myname if not os.path.isabs(name): name = os.path.join(root, cwd, name) name = os.path.normpath(name) if auditor is None: auditor = pathauditor(root) if name != rootsep and name.startswith(rootsep): name = name[len(rootsep):] auditor(name) return util.pconvert(name) elif name == root: return '' else: # Determine whether `name' is in the hierarchy at or beneath `root', # by iterating name=dirname(name) until that causes no change (can't # check name == '/', because that doesn't work on windows). The list # `rel' holds the reversed list of components making up the relative # file name we want. rel = [] while True: try: s = util.samefile(name, root) except OSError: s = False if s: if not rel: # name was actually the same as root (maybe a symlink) return '' rel.reverse() name = os.path.join(*rel) auditor(name) return util.pconvert(name) dirname, basename = util.split(name) rel.append(basename) if dirname == name: break name = dirname # A common mistake is to use -R, but specify a file relative to the repo # instead of cwd. Detect that case, and provide a hint to the user. hint = None try: if cwd != root: canonpath(root, root, myname, auditor) relpath = util.pathto(root, cwd, '') if relpath[-1] == pycompat.ossep: relpath = relpath[:-1] hint = (_("consider using '--cwd %s'") % relpath) except error.Abort: pass raise error.Abort(_("%s not under root '%s'") % (myname, root), hint=hint) def normasprefix(path): '''normalize the specified path as path prefix Returned value can be used safely for "p.startswith(prefix)", "p[len(prefix):]", and so on. For efficiency, this expects "path" argument to be already normalized by "os.path.normpath", "os.path.realpath", and so on. See also issue3033 for detail about need of this function. >>> normasprefix(b'/foo/bar').replace(pycompat.ossep, b'/') '/foo/bar/' >>> normasprefix(b'/').replace(pycompat.ossep, b'/') '/' ''' d, p = os.path.splitdrive(path) if len(p) != len(pycompat.ossep): return path + pycompat.ossep else: return path # forward two methods from posixpath that do what we need, but we'd # rather not let our internals know that we're thinking in posix terms # - instead we'll let them be oblivious. join = posixpath.join dirname = posixpath.dirname